If you’re planning major renovations to a flat roof commercial building in the Northern U.S., you may want to take into consideration that flat roofs — particularly older ones — don’t handle snow accumulation very well, particularly if they have a poorly designed or blocked drainage system.

That’s particularly true on the East Coast where snow tends to be wetter and denser than the western part of the country. If your building is getting a complete makeover, consider installing a steep slope metal retrofit roofing system that will provide a long-term solution for your snow and drainage problems. Steeper roof slopes shed snow more effectively. That’s why greater roof slopes are common on commercial and residential buildings in the northern states and in mountainous snow-prone regions.

According to FEMA’s Snow Load Safety Guide, roof pitch that exceeds the angle of repose of snow results in snow sliding. The angle of repose is the maximum angle at which snow will not slide–approximately a 30-degree roof slope often referred to as a 6:12 or 7:12 slope.

Even if you already have an old steep or low sloped roof, remember that abrasive roofing materials are less slippery and do not shed snow as easily as a slippery surface. Tactile roof materials include asphalt shingles and aggregate surface build-up membranes. Slippery roof materials including standing seam metal and single-ply membrane roofing.

Plus, you’ll get a lot longer life out of your retrofit metal roof and in many cases, the cost difference between a conventional roof tear-off and replacement compared to a retrofit metal roof system is a return on investment which can be recouped in just a few short years. And in many cases, your new steep slope roof provides an effective hiding place for rooftop mechanical systems that collect snow drifts.

So, if you’re planning any major renovations on your flat roof commercial structure this Spring, remember where you live and what can happen in wintertime–and prevent it from happening again.